Initialize layoutCache in SelfSizingStereoCell (#5422)
Initialize layoutCache in SelfSizingStereoCell (#5422)

Whoop! Forgot to initialize the layout cache in the `MDCSelfSizingStereoCell`.
material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios